Alloy steel



UNITED STATES PATENT OFFICE.

CHARLES MORRIS JOHNSON, OF AVALON, PENNSYLVANIA.

ALLOY STEEL.

No Drawing.

I have discovered a new alloy steel, the

composition of which ma be varied within limits to be hereinafter efined, which possesses to a marked degree many highly desirable physical properties. It is non-magnetic. It is strongly resistant to scaling by heat, and to the action even of the oxyacetylene flame. It resists rust, as Well as attack by acids. It is also non-brittle, but. is tough and highly ductile, while sufficiently hard for a great variety of uses.

Thisnew alloy steel is a chromium-nickelsilicon steel, containing not less than ten per cent of chromium, not le S than nine per cent of nickel, and not less t an one per cent of silicon. The chromium should not exceed twenty per cent, the nickel twenty-five per cent, or the silicon ten per cent. The chromium and nickel are advantageously used in substantially equal proportions, though this is subject to some variation. For instance in some cases I have used 16 per cent chromium with 10 per cent nickel twenty per cent each of nickel and chromium and from three to four per cent silicon. Though higher carbon may be used for particular purposes, the carbon content should not ordinarily exceed one per cent, and-for most purposes I prefer to keep the carbon below .40 per cent.

When tested in comparison with other steels considered as resistant as any so far known, by immersion for 24 hours in both dilute sulphuric acid and dilute hydrochloric acid, the steels of the compositions acid (32% acid') Specification of Letters Patent. Patentd June 27, 1922.

Application filed August 6, 1920. Serial No. 401,656.

above stated were much more lightly attacked, indeed hardly attacked at all. The steel is also highly resistant to dilute nitric water, while the other so-called non-corrosive steels were badly rusted, my steel was only slightly stained at the water level, without any progressive rusting at all.

My steel cannot be burned, that is to sa rendered crystalline and brittle, at a temperature as high as 2400 F. In fact after having been exposed to that temperature, tests showed its elongation and its reduction in In still other tests in area to be'each 67 per cent. It-is consequently very workable hot, and it can be formed cold into many varieties of vessels and uten sils in which its resistant properties are desirable. Being also of high tensile strength it may be used for boiler-tubes, cutlery, en-

gine parts in internal combustion engines, and dies for die casting. And it may be used generally for purposes where toughness, or resistance to heat or corrosion are re uiredt is a matter of common experience that nickel and cobalt have manyuli-ke chemical properties, and that their metallurgical effects in alloy steels are generally alike, so

I desire it to be understood that in the appended claim I intend to cover the use of cobalt as a substitute for nickel in whole. or in part. The steel may of course contain the usual small quantities of manganese, etc

and other alloying elements may also be employed without departure from the invention.

I claim as my lnventionz Steel containing from about ten per cent to about twentyper cent of chromium, from about nine per cent to about twenty-five per cent of nickel, and from about one per cent to about ten per cent of silicon.

In testimony whereofv I have hereunto set my hand.

CHARLES MORRIS JOHNSON. Witnesses:

G. G. TRILL, MARSHALL A. Onm's'rr. 

